1. Field of the Invention
The present invention relates to an information recording apparatus and a tamper prevention method (falsification preventing method) for the information recording apparatus, which performs tamper prevention processing when information such as audio and video is recorded.
2. Description of the Related Art
There is proposed an information recording apparatus that in recording information such as audio, in order to allow usage of the information as an evidence at a later date, performs tamper prevention processing in recording audio data (see, for example, Japanese Patent Laid-Open No. 2000-173185 (hereafter referred to as Patent Literature 1)).
In general, at the time of playing back audio data, in some cases, various types of editing processing such as deleting a time period in which audio or other data does not exist, or noise removing processing are performed. Furthermore, in some cases, at the time of playing back video image data, various types of editing processing such as deleting images in a time period during which images are disturbed or audio is not included, or noise removing processing are performed. In addition, in some cases, editing processing needs to be performed to extract a target audio or video from audio data or video image data.
However, in the case where tamper prevention processing is performed, for example, on audio data or video data at the time of recording audio or video, it is not possible to perform editing processing on the information after recording. As for information recorded at the time of audio recording or video recording, tamper prevention is not always necessary for all pieces of information recorded at the time of audio recording or video recording, and there are many cases where only decisive moments are important as an evidence. Nevertheless, editing processing cannot be not performed on the information recorded with information recording equipment having a tamper prevention processing function, which leads to a deterioration in operability thereof.